<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<html>
<head>
<!-- Copyright 1997 The Open Group, All Rights Reserved -->
<title>fmod</title>
</head><body bgcolor=white>
<center>
<font size=2>
The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

</font></center><hr size=2 noshade>
<h4><a name = "tag_000_005_119">&nbsp;</a>NAME</h4><blockquote>
fmod - floating-point remainder value function
</blockquote><h4><a name = "tag_000_005_120">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

#include &lt;<a href="math.h.html">math.h</a>&gt;

double fmod(double <i>x</i>, double <i>y</i>);
</code>
</pre>
</blockquote><h4><a name = "tag_000_005_121">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>fmod()</i>
function returns the floating-point remainder of the division of
<i>x</i>
by
<i>y</i>.
<p>
An application wishing to check for error situations should set
<i>errno</i>
to 0 before calling
<i>fmod()</i>.
If
<i>errno</i>
is non-zero on return, or the return value is NaN, an error has occurred.
</blockquote><h4><a name = "tag_000_005_122">&nbsp;</a>RETURN VALUE</h4><blockquote>
The
<i>fmod()</i>
function returns the value
<i>x - i * y</i>
for some integer
<i>i</i>
such that, if
<i>y</i>
is non-zero, the result has the same sign as
<i>x</i>
and magnitude less than the magnitude of
<i>y</i>.
<p>
If
<i>x</i>
or
<i>y</i>
is NaN, NaN is returned and
<i>errno</i>
may be set to [EDOM].
<p>
If
<i>y</i>
is 0,
NaN is returned
and
<i>errno</i>
is set to [EDOM], or 0 is returned and
<i>errno</i>
may be set to [EDOM].
<p>
If
<i>x</i>
is &plusmn;Inf, either 0 is returned and
<i>errno</i>
is set to [EDOM],
or NaN is returned and
<i>errno</i>
may be set to [EDOM].
<p>
If
<i>y</i>
is non-zero, <i>fmod</i>(&plusmn;0,<i>y</i>) returns the value of
<i>x</i>.
If
<i>x</i>
is not &plusmn;Inf, <i>fmod</i>(<i>x</i>,&plusmn;Inf) returns the value of
<i>x</i>.
<p>
If the result underflows, 0 is returned and
<i>errno</i>
may be set to [ERANGE].
</blockquote><h4><a name = "tag_000_005_123">&nbsp;</a>ERRORS</h4><blockquote>
The
<i>fmod()</i>
function may fail if:
<dl compact>

<dt>[EDOM]<dd>
One or both of the arguments is NaN,
or
<i>y</i>
is 0, or
<i>x</i>
is &plusmn;Inf.

<dt>[ERANGE]<dd>
The result underflows.

</dl>
<p>
No other errors will occur.
</blockquote><h4><a name = "tag_000_005_124">&nbsp;</a>EXAMPLES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_005_125">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
Portable applications should not call
<i>fmod()</i>
with
<i>y</i>
equal to 0, because the result is implementation-dependent.
The application should verify
<i>y</i>
is non-zero before calling
<i>fmod()</i>.
</blockquote><h4><a name = "tag_000_005_126">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_005_127">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="isnan.html">isnan()</a></i>,
<i><a href="math.h.html">&lt;math.h&gt;</a></i>.
</blockquote><h4>DERIVATION</h4><blockquote>
Derived from Issue 1 of the SVID.
</blockquote><hr size=2 noshade>
<center><font size=2>
UNIX &reg; is a registered Trademark of The Open Group.<br>
Copyright &copy; 1997 The Open Group
<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]

</font></center><hr size=2 noshade>
</body></html>

